Option 19 to 03

Also you can grab the manual from IPDB which covers this..... setting 03 is actually 1/25¢, 4/$1. Not really clear on that one but one of the coin chutes would give 4 credits in that situation - the game doesn't know what kind of currency is going into it, williams calls this units. You can also set the coin option 19 to 00 which will allow you set the next settings as you like.

20,21,22 are unit multipliers for the coin slots.... so 01 for all 3.
23 is # of units required for credits, so 01 for 1/1 ratio.
24 is coin unit bonus, set to 00 to not award bonus credits
25 is minimum coin units, set to 00.

This would give you 1 coin/1 credit for any of the 3 coin chutes.

Ignore the manual saying cents etc it's just units. It is confusing as Williams was the only company to do it this way.
But if you want one coin in one credit it's one unit per slot and one unit per credit.